On Windows 10, using Thunderbird client with Mindspring email, email with url won't come through

Greg A

Hey. I just noticed an aberration - that on approximately March 26 I was no longer receiving email to myself which contained a url. The email will show up in my Sent folder but it doesn't come through to my inbox, nor does Bitdefender Total Security have any log or info on it that I can find.

However, if I send myself and also cc my gmail account, the email goes through to both my mindspring and my email accounts.

Also, if I use Webmail (earthlink.net - earthlink subsumed mindspring a while back), my mindspring email with the url will go through to my Thunderbird/Mindspring on Windows 10.

I see Bitdefender stamps in the headers of the emails that go through so I'm thinking Bitdefender may be intervening somehow.

Any help will be appreciated.

Alexandru_BD

Hello @Greg A,

I think the core of this behavior suggests a few things. First, based on your description of the issue encountered, the issue isn't with the sending process, because it works for cc’ed Gmail. Secondly, webmail works, so the email is not being blocked on the server side. By the looks of it, the problem arises only when Thunderbird is fetching from Mindspring. I think there are a few possibilities to consider here, and the first one that comes to mind is that Bitdefender might be interfering with Thunderbird POP/IMAP traffic, especially if HTTPS scanning is in place, so Thunderbird never sees or downloads emails containing URLs due to local filtering.

Or, since Thunderbird has local junk/spam filtering and message rules, if it detects a message with a URL as suspicious, it may route it to Junk, delete it, or even block it silently, if corrupted headers trigger spam rules.
However, I think this is unlikely, since Webmail still delivers, and your cc’d Gmail works. Still worth checking though.

To find out if Bitdefender somehow affects the delivery of emails, I would recommend to disable some of its security modules temporarily, and check if the issue persists afterwards. For example, you could disable Web Protection and also Encrypted web scan under the Online Threat Prevention module, and see if this makes a difference. Furthermore, you can test with other modules off, and here's the complete guide on how to disable them, for troubleshooting purposes:

https://www.bitdefender.com/consumer/support/answer/28557/

Just to rule out any Thunderbird rule or local corruption, close Thunderbird, then run thunderbird.exe -p from Start → Run or CMD, create a new profile, reconfigure your Mindspring account (IMAP recommended), and send yourself an email containing an URL. If it works this way, the original profile most likely has a corrupted filter or config.

Another thing you could try is to add Thunderbird as a trusted application in Bitdefender. Open Bitdefender and go to Protection → Advanced Threat Defense → Settings and add Thunderbird (thunderbird.exe) as an exception there. Also try this under Online Threat Prevention → Manage Exceptions.

Let me know if anything here helped.

Regards

Greg A

Thanks Alexandru!

Still looking at this and have followed some of your suggestions and I don't think Bitdefender is causing our problem.

And I've found that Thunderbird did an update right around the date my url emails started failing. So I'm gonna look into that.

Again, thanks!

Alexandru_BD

You are most welcome, thank you for following up here. 🤝